From: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
To: mingo@elte.hu
Cc: Ingo Molnar <mingo@elte.hu>,
vatsa@in.ibm.com, clameter@sgi.com, tglx@linutronix.de,
arjan@linux.intel.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC] Patch: dynticks: idle load balancing
Date: Wed, 7 Feb 2007 14:19:19 -0800 [thread overview]
Message-ID: <20070207141919.C19581@unix-os.sc.intel.com> (raw)
In-Reply-To: <20070130135709.B32010@unix-os.sc.intel.com>; from suresh.b.siddha@intel.com on Tue, Jan 30, 2007 at 01:57:09PM -0800
On Tue, Jan 30, 2007 at 01:57:09PM -0800, Siddha, Suresh B wrote:
> Please let me know if you still see this issue with the latest -rt kernel.
>
> On Tue, Jan 16, 2007 at 12:35:05PM +0100, Ingo Molnar wrote:
> > on the latest -rt kernel, when the dynticks load-balancer is enabled,
> > then a dual-core Core2 Duo test-system increases its irq rate from the
> > normal 15/17 per second to 300-400/sec - on a completely idle system(!).
> > Any idea what's going on? I'll disable the load balancer for now.
Ok. got time to look into this.
The answer is simple. load_balancing in the recent kernels is happening
using SCHED_SOFTIRQ and in -rt tree that happens not in the idle process
context but in the context of softirqd for SCHED_SOFTIRQ.
This breaks the dynticks load balancer and also the regular idle load balancing
too :(
Am on to fixing the problem now :)
thanks,
suresh
next prev parent reply other threads:[~2007-02-07 22:53 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-11 23:53 [RFC] Patch: dynticks: idle load balancing Siddha, Suresh B
2006-12-13 22:43 ` Ingo Molnar
2006-12-13 23:13 ` Ingo Molnar
2006-12-13 23:03 ` Siddha, Suresh B
2006-12-13 23:31 ` Ingo Molnar
2006-12-13 23:19 ` Siddha, Suresh B
2006-12-14 0:34 ` Ingo Molnar
2006-12-19 20:12 ` Ingo Molnar
2006-12-19 21:12 ` Siddha, Suresh B
2007-01-16 11:35 ` Ingo Molnar
2007-01-30 21:57 ` Siddha, Suresh B
2007-02-07 22:19 ` Siddha, Suresh B [this message]
2007-02-17 2:03 ` [patch 1/2] sched: fix idle load balancing in softirqd context Siddha, Suresh B
2007-02-17 2:08 ` [patch 2/2] sched: dynticks idle load balancing - v2 Siddha, Suresh B
2007-02-21 20:23 ` Andrew Morton
2007-02-22 3:14 ` Nick Piggin
2007-02-24 2:01 ` [patch] sched: dynticks idle load balancing - v3 Siddha, Suresh B
2007-02-22 3:26 ` [patch 2/2] sched: dynticks idle load balancing - v2 Nick Piggin
2007-02-22 22:33 ` Siddha, Suresh B
2007-02-23 3:43 ` Nick Piggin
2007-02-17 14:42 ` [patch 1/2] sched: fix idle load balancing in softirqd context Steven Rostedt
2007-02-21 6:25 ` Siddha, Suresh B
2007-02-21 20:13 ` Andrew Morton
2006-12-13 23:48 ` [RFC] Patch: dynticks: idle load balancing Ingo Molnar
2006-12-20 0:49 ` Steven Rostedt
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